Chemical Reactions
When Molecules Change
What a Reaction Is
A chemical reaction is a process in which starting substances, called reactants, are transformed into new substances, called products, by rearranging atoms and bonds.
Conservation of Matter
In a chemical reaction, atoms are not created or destroyed in ordinary chemical changes; they are rearranged.
Balanced Equations
A balanced chemical equation shows the same number of each kind of atom on both sides of the reaction, reflecting conservation of matter.
Reaction Vocabulary
What are the starting substances in a chemical reaction called?
Reactants are the substances present before the reaction occurs.
Correct answer: Reactants
What do we call the new substances formed in a reaction?
Products are the substances made by the reaction.
Correct answer: products
What does a balanced equation show?
Balanced equations preserve the count of each atom type.
Correct answer: That the same number of each atom appears on both sides
How to Read a Reaction
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1
Identify the reactants.
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2
Identify the products.
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3
Count atoms on each side.
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4
Check whether the equation is balanced.
In ordinary chemical reactions, are atoms created or destroyed?
Atoms are rearranged, not created or destroyed, in ordinary chemical reactions.
Correct answer: no